Heat pump efficiency ratings explained
SEER2, HSPF2 and COP all measure how efficient a heat pump is — but each tells you something different. Here is what they mean.
The three efficiency ratings
| Rating | Measures | Higher = |
|---|---|---|
| SEER2 | Seasonal cooling efficiency | Cheaper to cool |
| HSPF2 | Seasonal heating efficiency | Cheaper to heat |
| COP | Instant heat moved per unit of electricity | More efficient at that moment |
SEER2 and HSPF2 are the updated (2023+) versions of SEER and HSPF, tested under tougher conditions, so the numbers run slightly lower than the old ratings. COP is a simple ratio: a COP of 3 means the unit delivers 3 units of heat for every 1 unit of electricity.
What numbers to target
- SEER2: 15+ is solid; 16–20+ for high-efficiency units.
- HSPF2: roughly 7.5–10; higher is better for cold-climate heating.
- COP: 2.5–4 is typical; cold-climate units hold a higher COP at low temperatures.
For incentives and rebates, look for ENERGY STAR (and ENERGY STAR Cold Climate) certified models, which meet minimum efficiency tiers.
Federal minimums (2023+): new heat pumps must meet regional DOE standards — about 14.3 SEER2 / 7.5 HSPF2 in the South and 13.4 SEER2 / 7.5 HSPF2 in the North. ENERGY STAR models exceed these.
What about EER2? EER2 measures cooling efficiency at a single hot temperature (95°F), so it matters most in hot climates — look for a higher EER2 there, alongside SEER2.
SEER vs SEER2: SEER2 replaced SEER in 2023 with a tougher test, so SEER2 numbers run roughly 5% lower than the old SEER, and HSPF2 about 15% lower than HSPF, for the same unit.
Why efficiency matters
A higher-efficiency heat pump uses fewer kWh for the same comfort, which lowers your bills every year it runs. Use our energy-use calculator to see how HSPF2 changes your annual heating cost, and the savings calculator to compare against your current system.
Frequently asked questions
What is a good SEER2 and HSPF2 for a heat pump?
SEER2 15+ and HSPF2 around 8–10 are good targets; high-efficiency and cold-climate units go higher.
What is COP for a heat pump?
Coefficient of Performance — the ratio of heat delivered to electricity used. A COP of 3 means 3 units of heat per 1 unit of electricity.
What is the difference between SEER and SEER2?
SEER2 is the updated test standard (2023+) using higher external static pressure, so SEER2 numbers are slightly lower than old SEER for the same unit.
Related
Sources & further reading
Educational guide, reviewed against US DOE & ENERGY STAR guidance and updated June 2026. Estimates only — not a substitute for a professional assessment or Manual J load calculation.